The response of cells to various stimuli can provide important information about the cells. This information can be useful from a research perspective in discovering and ultimately understanding the reactions of cells to these stimuli. These responses can also have utility in testing the viability and health of the cells. For example, healthy pancreatic islet cells when stimulated with glucose will produce insulin. The rate of production of insulin can provide an indication of the viability of these cells. In order to determine the rate of production, several samples are often taken at intervals and tested for the presence of insulin.
Perifusion is the process of passing a fluid past cells or tissue immersed in the fluid. Apparatus for performing perifusion experiments are usually made from available equipment in the laboratory. The cells are placed into a packed column and inlet and outlet tubing is attached to the column. A solution including the stimuli, such as glucose, is flowed through the column and samples are periodically taken from the column through the outlet and tested for the presence of insulin. The process is time and labor intensive. An attendant must regularly draw and test the samples. In order to provide sufficient data, several samples are usually run simultaneously. In this case, output must be regularly taken from several columns and the samples analyzed for the presence of insulin or whatever products are being measured.